US3731739A

US3731739A - Wash out method and apparatus

Info

Publication number: US3731739A
Application number: US00087783A
Authority: US
Inventors: D Herd
Original assignee: Rockwell Manufacturing Co
Current assignee: Cooper Industries LLC; Rockwell Manufacturing Co
Priority date: 1970-11-09
Filing date: 1970-11-09
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08
Also published as: GB1361666A

Abstract

Method and apparatus for removing underwater well pipe connected below the mudline by washing out mud surrounding a portion of the pipe. The method utilizes a special joint which comprises two tubular members engageable with each other, one of which has wash out ports through its walls. A sleeve member is mounted in the tubular members for longitudinal movement from a first position where it blocks flow through the wash out ports to a second position where it permits such flow. The sleeve member when in the first position also locks the tubular members against disengagement but allows their disengagement when in the second position. The upper tubular member is rotatably mounted in an external casing which shields the upper tubular member from the mud whereby it can be turned to disengage it from the lower tubular member.

Description

United States Patent 1 [111 3,731,739 Herd 1- May 8, 1973 [54] WASH OUT METHOD AND Primary Examiner-Marvin A. Champion APPARATUS Assistant Examiner-Terrell P. Lewis [75] Inventor: David P. Herd, Houston, Tex. AnomeyMurray Robmson and Ned Conley [73] Assignee: Rockwell Manufacturing Company, [57] ABSTRACT Houston Method and apparatus for removing underwater well [22] Filed: Nov. 9, 1970 pipe connected below the mudline by washing out mud surrounding a portion of the pipe. The method [21] Appl' 87783 utilizes a special joint which comprises two tubular members engageable with each other, one of which [52] U.S. Cl. ..l66/.5, 285/86, 166/3 1 5 has wash out ports through its walls. A sleeve member [51] Int. Cl. ..E2lb 7/12, E2lb 43/01 is mounted in the tubular members for longitudinal [58] Field of Search ..l66/3l5, 77.5, 85, movement from a first position where it blocks flow l -5; 285/ 391 through the wash out ports to a second position where it permits such flow. The sleeve member when in the References Cited first position also locks the tubular members against disengagement but allows their disengagement when UNITED STATES PATENTS in the second position. The upper tubular member is 2,947,363 8/1960 Sackett etal ..l66l224 ta ly m unted in an external casing which shields 3,421,580 l/1969 Fowler et aL... ..l66/.5 the upper tubular member from the mud whereby it 3,294,174 12/1966 Vincent can be turned to disengage it from the lower tubular 3,400,950 10/1968 Quebe etal. ..285/l8 member 3,492,026 l/l970 Ahlstone ..l66/87 X 38 Claims, 4 Drawing Figures Patented May' 8, 1973 3,731,739

3 sheets-sheet 1 flay/'0 R fi /d INVENTOR.

Patented May 8, 1973 3 Sheets-Sheet 2 5 Sheets-Sheet 3 Patented My 8, 1973 was INVENTOR.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention concerns underwater petroleum drilling operations. More specifically, it is concerned with methods and apparatus for disconnecting joints that may be surrounded by compacted mud or the like.

2. Description of the Prior Art Underwater drilling for oil and gas has become commonplace in the last few years. In order to develop these offshore petroleum reservoirs it is necessary to drill a large number of exploratory wells. These wells are usually permanently abandoned after exploratory drilling. Coast Guard Regulations require that the abandoned well conductor and easing strings be below the mudline.

In the past, one of several expensive or hazardous methods of removing this equipment to a point below the mudline has been required. Hazardous explosives have been used to sever the casing and conductors below the mudline. Inside mechanical cutters, which are expensive and require as much as eight hours of rig time, have also been used. Sometimes divers are used to release the equipment. Neither of these methods is completely desirable.

SUMMARY OF THE INVENTION The present invention concerns an improved method and apparatus for removing well pipe which is connected to other apparatus beneath the floor of a body of water wherein the improvement comprises the steps of providing a special joint between the apparatus and the pipe which extends upwardly to a space above the body of water; pulling upwardly on a portion of the special joint to open passage means providing flow communication between the interior of the pipe and its surrounding environment; and circulating washing fluid through the passage means to remove excess mud and any other materials surrounding the special joint. After the mud is washed out a part of the special joint and the pipe may be removed from the well. The specialjoint is disengaged by rotation of less than three hundred and sixty degrees. An external casing, within which the pipe is rotatably mounted, shields the pipe from the mud to facilitate such disengagement, following which the easing is removed along with the pipe and part of the special joint.

The apparatus comprises a special joint including a first tubular member engageable with a second tubular member and a sleeve member telescopically engageable with the tubular members. The first tubular member has flow ports through its walls. The sleeve member is movable independently of the tubular members from a first position, whereby the flow ports are blocked thereby, to a second position whereby they are unblocked. The sleeve in its first position also locks and prevents disengagement of the first and second tubular members. A riser pipe is connected to the second tubular member. An external casing, surrounding the riser pipe and shielding it from the mud, is connected to the second tubular member by means which permits rotation of the riser pipe and second tubular member relative to the external casing.

The method and apparatus used is extremely simple, economical and practical. Accidental disengagement is prevented and easy removal of the pipe and abandonment of the well in compliance with government regulations is accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will become apparent from the description which follows when taken in conjunction with the drawings in which:

FIG. 1 is a schematic representation of a drilling rig and platform in use on an underwater well with which the present invention might be used;

FIG. 2 is an elevational view, partially in section, showing an underwater installation employing one embodiment of the invention, with the special joint in its running or engaged position;

FIG. 3 is an elevational view, partially in section, similar to FIG. 2 but showing the special joint in its circulating or disengaging position; and

FIG. 4 is a detailed elevational view in section of the special joint of FIGS. 2 and 3 according to a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 1. Conductor Casing and Risers FIG. 1 of the drawings schematically represents a drilling rig 10 mounted on a drilling platform 11 above a body of water 12. A conductor casing 20 penetrates the subsurface 13 of the water body and is connected below the mudline to a conductor riser or pipe 23 by special joint 50. The conductor riser 23 extends upwardly from the special joint to a level above the mudline where it is connected at 24 to a string of conductor risers 25. The string extends through the water to the platform 11 where it is surmounted by a landing base 14 and drilling control equipment 15. Several hanger-heads, casing strings and tubing strings maybe supported within conductor 20. External casing 26 shields the riser 23 from the mud.

2. Surface Casing and Risers Referring now to FIG. 2, a surface casing hanger 30 and attached surface casing (not shown) are supported within conductor 20 on support ring 31. Support lugs 32 rest on upwardly facing support shoulder 24 of support ring 31. Flow passages 33 between lugs 32 allow fluid flow for cement returns and the like. A riser 38 is attached to hanger 30 by a backoff sub 37 and extends to the drilling platform. Hanger 30 may have an internal support shoulder which may subsequently provide support for another casing string.

3. Special Joint Between Conductor Casing and Risers Connected between conductor 20 and riser 23 is the special joint, designated generally at 50, according to one embodiment of the invention. .Ioint 50 may be welded to a short length of pipe 40 which is in turn welded to support ring 31 and conductor 20. Alternately the female part 60 of joint 50 may be an integral part of ring 31.

4. Cement Wash Out Ports in Joint Between Surface Casing and Risers The joint 50 is shown in its running position in FIG. 2. hanger 30, its attached surface casing, backoff sub 37 and riser 38 would all be lowered together to the support position shown. At this point, cementing would take place by pumping the cement mixture downwardly through riser 38 and the surface casing, then upwardly in the annular space between the surface casing and conductor 20. More than likely enough cement would be pumped into the well to completely surround hanger 30 and possibly even the upper portion of backoff sub 37. If the cement were allowed to harden around backoff sub 37, it would be difficult, if not impossible, to disconnect riser 38 for removal. Therefore, the excess cement might be removed by circulating through wash out ports 39. Further drilling would then proceed until the well is tested. The wash out ports are valve controlled and are normally closed. In place of the wash out ports indicated at 39, valve controlled ports such as shown in U. S. Pat. No. 3,508,609 may be used.

5. Special Joint: Breech Block Connection Referring also now to FIG. 4, the special joint 50 comprises a female member 60, a male member 70 and locking sleeve 80. In the particular embodiment shown male and

female members

60, 70 are attached in a telescopic breech-block type connection. A full description of such a connection is given in copending U. S. Pat. application Ser. No. 728,081, now US. Pat. No. 3,442,536. For the present application it is sufficient to say that segmented threads 61 of a square non-lead profile spaced thirty degrees apart are milled in the female member 60 for engagement with corresponding segmented threads 71 of the male member 70. Smooth milled out areas are provided between the

thread segments

61, 71. For descriptive purposes the thread segments 61, U1 are referred to as lands and the milled out areas as grooves. Engagement is accomplished by inserting the lands of the male member 70 into the grooves of the female member 60, then rotating the male member thirty degrees until the lands of each member are in full engagement. A positional stop 73 on the male member 70 cooperates with lugs 63 around female member 60 to limit rotation to thirty degrees for full engagement. Disengagement is accomplished by thirty degree rotation in the opposite direction. Seal rings 74 create a fluid-tight seal. The riser connections 24 (FIG. 1) may be of similar construction but additional manually releasable locking lugs are provided to prevent disengagement so that the connection can transmit torque in both directions, reverse turning being required to disengage joint 50.

6. Special Joint: Valve and Locking Sleeve The lower interior of female joint 60 is provided with a circumferential shoulder 64 interrupted by slots 65 at regular intervals. The purpose of slots 65 will be better understood subsequently. Several radial wash outports 66 are drilled through the wall of female member 60.

Mounted on the interior of

members

60 and 70 is the sleeve member 80. The bore of sleeve 80 is smooth except for a plurality of J-slots- 81 around its upper edge. The J-slots 81 are cut through the reduced external diameter upper portion of sleeve 80. Then a thin collar portion 82 is slipped around the reduced exterior and welded to sleeve 80. A tapered shoulder 83 on collar 82 cooperates with seal ring 75' on male member to "prevent trash from entering the annular space 84 between member 70 and collar 82. By leaving such an annular space, sliding friction between the sleeve 80 and male member 70 is reduced. Several spring loaded pins 76 are mounted on male member 70 so as to rest against collar 82 when sleeve 80 is in the running position.

Near the midportion of sleeve 80, its diameter is only slightly less than the internal diameter of male member 70. A plurality of shear pins are installed in matching holes provided in the walls of male member 70 and sleeve to hole sleeve 80 in the running or engaged position. A plurality of vertical guide slots 85 are milled on the exterior of sleeve 80 and a plurality of locking pins 77 and nuts 78 are installed in male member 70 so that the end of each of the pins 77 engages one of the guide slots 85. This arrangement will prevent rotational movement but will allow vertical movement of sleeve 80 relative to male member 70. The diameter of sleeve 80 is reduced again directly below locking pin 77 to reduce sliding friction.

The lower end of sleeve 80 fits female member 60 in a close sliding fit and in its running or lowered position as shown in FIGS. 2 and 4 closes washout ports 66 with the cooperation of annular seal members 86, 87. The lower end of the sleeve 80 rests on female member shoulder 64 and is provided with depending lugs 88 which cooperate with slots 65 to lock sleeve 80 and male member 70 against rotation relative to female member 60.

In the running or engaged position of FIGS. 2 and 4, joint 50 permits fluid circulation upwardly in the annular space surrounding hanger 30 and riser 38. In this position wash out ports 66 are closed by the lower end of sleeve 80. The engagement of sleeve lugs 88 and slots 65 also prevents the disengagement of the breechblock connection between male and

female members

70, 60.

7. Riser Shield Casing Referring now particularly to FIG. 2, the external casing 26 has a larger inner diameter than the outer diameter of riser 23 leaving an annular space 90 therebetween. At the upper end of external casing 26 it is centered relative to the riser by a stabilizer ring 92. The lower part 94 of ring 92 fits telescopically within the upper end of riser 23, making a free, loose, nonfrictional fit therewith to allow easy relative rotation therebetween. The upper part 96 of the stabilizer ring is of larger outer diameter, extending out over the upper end of the riser to keep downward axial loads off of the riser. The ring is welded to the riser at 98.

The external shield casing 26 is of increased wall thickness at its lower end 100. The lower end 100 is fitted telescopically over a cylindrical land 102 provided above shoulder 104 on the upper pin or male member 70 of the special joint, making a free, loose, non-frictional fit therewith. An antifriction thrust bearing comprising ball race groove 106 in land 102 and ball race groove 108 inside lower end 100 (of the shield casing 26) and a plurality of balls 110, holds the shield casing 26 against axial movement relative to pin member 70 and the riser 23 connected thereto while allowing rotation of the pin member and riser relative to the shield casing. There is a slight clearance between the lower face 112 of the shield casing and the shoulder 104 on the pin member 70, so that the weight of the shield casing is carried by the thrust bearing.

To keep mud out of the annular space 90 between the shield casing and riser, an annular seal means 114 is provided between lower end 100 (of the shield casing) and land 102 of the pin member 70. The seal means may be an elastomeric O-ring disposed in a groove in land 102.

Since water will enter annulus 90 at the upper end thereof, a drain port 116, normally closed by threaded plug 118, is provided in the lower end 100 of the shield casing. This facilitates emptying annulus 90 when the riser and shield have been retrieved and are being cleaned up after use.

The riser 23 is welded to the pin member 70 at 120. To facilitate assembly of the shield casing 26 with a pin member 70 of a previously manufactured apparatus wherein the riser 23 was unshielded, it is convenient to cut the riser a little above weld 120 and upon reassembly to weld the riser 23 together again at 122. In the case of original manufacturing one weld at 120 should suffice.

To allow assembly of the shield casing to the pin member 70, there is provided a port 124 (see FIG. 4) through which the balls 110 can be inserted after lower end 100 of the shield casing has been slipped over land 102. The port 124 is then closed with threaded plug 126.

The lower end 100 of the shield casing is preferably made of an initially separate piece and then welded to the rest of the shield casing at 128.

The female or box part 130 of breech block connection 24 forms the upper part of riser 23 and is welded in place at 132. This may be done after shield casing 26 and stabilizing ring 96 have been slipped over the rest of riser 23.

8. Method After exploratory drilling is completed and all tests are complete, the well may be abandoned. All tubing, casing risers etc. are removed from the well. Riser 38 and backoff sub 37 are disconnected from hanger 30 and removed.

The final step is to remove conductor riser 23. Since the mud around joint 50 may be compacted it might be difficult or impossible to disconnect were it not for the special design ofjoint 50.

To wash out the compacted mud around the joint 50 it is necessary to open the ports 66 so that water may be pumped into riser 23 and circulated through ports 66 as shown by the arrows in FIG. 3. This is accomplished by raising sleeve member 80 to the position shown in FIG. 3.

Referring again also to FIG. 4, sleeve member 80 is raised by lowering a tool (not shown) with radial pins thereon on a pipe string through riser 23 and allowing it to rotate until its pins fully engage J-slots 81. Then an upward pull causes shear pins 75 to be sheared, releasing sleeve 80 for upward movement. Spring loaded pins 76 engage vertical milled slots 85, preventing the sleeve from dropping back into its running position. The tool may then be removed and water circulated through ports 66. With the sleeve 80 in this position lugs 88 no longer engage slots 65. Therefore, after wash out, riser 23, male member 70, and sleeve 80 may be disengaged from female member 60 by thirty degree rotation for removal from the well. Then, the well may be abandoned with all abandoned equipment being buried beneath the mudline in accordance with Coast Guard Regulations.

Thus, a simple operated joint has been shown for quick and effective abandonment. The joint utilizes a sleeve member which not only serves as a circulating port control for mud wash out but also serves as a lock and release device for preventing joint disengagement and subsequently allowing the joint to be disconnected for removal of part of the joint and other attached apparatus.

While disconnecting the special joint by turning the pin member through thirty degrees and while retrieving the riser 23, pin member 70, and shield casing 26, it is permissible to maintain fluid flow at all times, initially through ports 66 and thereafter also through the pin member 70 when no longer in sealing engagement with box member 60 of the special joint. This would prevent the mud from settling back around the shield casing 26 and pin member 70 before they have been elevated above the mudline. Normally however, wash out would not be carried on during either the turning or pulling of riser 23 but instead would be effected prior to each such step or steps.

Referring now to FIG. 3, the apparatus is shown in the condition following wash out through ports 66 and prior to turning of the pin member 70 to disengage it from box member 60. In some cases, because of shield 26, such turning might be accomplished without the prior wash out step. However, it is to be noted that shield 26 does not prevent contact of the mud with a considerable area of pin member 70, so that it is preferred to perform the wash out step before turning the pin member to released position although it is also contemplated that the wash out step could be performed after such turning.

It is to be understood that the annulus 150 between the shield casing and mud formed by the wash out step isnot a void nor a pure water annulus but is in reality an annulus of mud whose compaction has been to a certain extent broken down by the water flow from ports 66. In the process of disconnecting the special joint 50, the shield casing 26 prevents the mud in annulus from contacting the riser 23, whereby it is easier to turn it the thirty degrees required for disengagement of pin member 70 from box member 60 of the special joint. Experience has shown that in ordinary usage the shield casing is a necessity to allow turning of the riser with the torque available at the rig, for the joint 50 is buried so deep, e.g. 10 to 25 feet, that the compaction of the mud cannot be broken down sufficiently with available pump pressure to allow turning of the riser if unshielded.

In some areas with light or non-compacting mud the shield casing may be unnecessary, in which case it can be omitted, as shown in the parent of the present continuation-in-part application. It may also be possible in some cases to turn to disengaged position and then pull the riser 23 with attached pin member 70 .and shield casing 26 without washing out or breaking down the compaction of the mud around the shield casing. and pin member 70. In such case the ports 66 could be omitted. The various permutations of the method in accordance with the invention appropriate to varying circumstances are set forth in the claims.

While a preferred embodiment of the invention has been described in detail, modifications thereof will occur to one skilled in the art without departing from the spirit of the invention.

I claim:

1. Method of removing well pipe means which extends from above a body of water through the water and earth exteriorly in contact with the earth to other apparatus beneath the floor of the body of water to which apparatus it is releasably connected by means of a special rotationally releasable joint including valve means openable to provide flow communication between the interior of said pipe means and its surrounding earth environment adjacent the lower end of the pipe means, comprising the steps of: opening said valve means, circulating washing fluid through said passage means to free the bond between the exterior of the pipe means and the earth surrounding said pipe means, turning the upper end of said pipe means to release said joint, and withdrawing said pipe means from said earth.

2. A method of removing well pipe means as set forth in claim 1, characterized in that said valve means is opened by extending a tool longitudinally through said pipe means from the upper end thereof into said special joint, engaging said tool with said valve means, and moving said tool.

3. A method of removing well pipe means as set forth in claim 1, characterized in that said tool is engaged with a portion of said valve means that is axially upwardly movable relative to the remainder of the valve means to open the valve means and which on further movement is freed from the rest of the valve means, and by the step of removing said portion of said valve means along with said pipe means.

4. A method of removing well pipe means as set forth in claim 3 characterized in that said release of said special joint is effected by turning said well pipe means less than 360.

5. Method according to claim 4 further characterized by shielding said pipe from said floor to facilitate said rotation of said special joint part to effect said disconnection.

6. Method according to claim 5 further characterized in that said shielding is effected by providing a casing around the pipe, and removing said casing simultaneously with said pipe and said part of said specialjoint.

7. Method according to claim 6 further characterized in that said circulation is commenced after said rotation.

8. Method according to claim 6 further characterized in that said circulation is commenced prior to said rotation.

9. Method according to claim 8 further characterized in that said circulation is continued during said rotation.

10. Method according to claim 9 further characterized in that said circulation is continued during removal of said pipe.

11. Method according to claim 10 further characterized in that said circulation is discontinued only after said part of said special joint is above the mudline.

12. A method of removing well pipe which is connected to other apparatus beneath the floor of a body of water, wherein the improvement comprises the steps of: providing a special joint between said apparatus and said pipe which extends upwardly to a space above said body of water; pulling upwardly on a portion of said special joint to open passage means providing flow communication between the interior of said pipe and its surrounding environment; and circulating washing fluid through said passage means to remove mud and any other material surrounding said special joint,

characterized by latching said portion of said special joint in an upward position to maintain said flow communication.

13. A well construction for removing pipe from an earth bore comprising a lower tubular member engaged with an upper tubular member and a sleeve member telescopically engageable within said tubular members, said upper and lower tubular members being positioned within and in contact with the wall of such earth bore over the outer length of said lower member and at least the lower portion of the outer length of said upper member, said lower tubular member having flow passage means through the walls thereof, said sleeve member being upwardly movable independently of said tubular members from an initial position whereby said flow passages are blocked by a portion of said sleeve member to a final position wherein the lower end of said sleeve member is above said flow passages, whereby said flow passages are unblocked, said sleeve member having a lesser axial extent than said tubular members and being provided with means attachable with a tool lowered through said upper tubular member into engagement with said sleeve to facilitate said upward movement of the sleeve from said initial position to said final position.

14. A well construction as set forth in claim 13 further comprising means for releasably connecting both tubular members when said sleeve member is in said initial position thereby preventing the disengagement of said upper and lower tubular members from each other.

15. A well construction as set forth in claim 14 characterized in that said sleeve member is longitudinally movable upward from said initial position to said final position by an upward force on such connected tool and without rotation relative to said tubular members. I

16. A well construction as set forth in claim 14 wherein said connection means is engageable on less than three hundred sixty degree rotation of said upper member relative to said lower member.

17. A well construction as set forth in claim 14 characterized in that one of said tubular members and said sleeve member are provided with guide means to prevent rotational movement but to permit longitudinal movement relative to each other.

18. A well construction as set forth in claim 13 characterized in that said upper tubular member and said sleeve member are provided with latch means engageable when said sleeve member is in said lower position to maintain said sleeve member in said lower position and without connecting said sleeve member with said lower tubular member.

19. Apparatus for use in removing pipe from a well comprising a lower tubular member engageable with an upper tubular member and a sleeve member telescopically engageable with said tubular members on the interior thereof, said lower tubular member having flow passage means through its walls, said sleeve member movable from a first position whereby said flow passages are blocked by a portion of said sleeve member to a second position whereby said flow passages are unblocked,

said apparatus being provided with guide means comprising at least one vertical slot on the exterior of said sleeve member and a pin projecting inwardly from said upper tubular member to confine movement of said sleeve member from said first to said second position to longitudinal motion relative to said upper member,

said upper and lower tubular members being provided with connection means disengageable on rotation of said upper member relative to said lower member; characterized in that said second tubular member is provided with latch means disposed on said upper tubular member and engageable with said sleeve member in said second position to maintain said upper position and without hindering the disengagement of said upper member from said lower member.

20. Apparatus for use in removing pipe from a well comprising a first tubular member engageable with a second tubular member and a sleeve member telescopically engageable with said tubular members on the interior thereof, said second tubular member having flow passage means through its walls, said sleeve member movable from a first position whereby said flow passages are blocked by a portion of said sleeve member to a second position whereby said flow passages are unblocked, characterized in that said sleeve member and said tubular members are provided with lock means engageable when said sleeve member is in said first position to prevent disengagement of said first and second tubular members.

21. Apparatus as set forth in claim characterized in that said lock means is disengageable on movement of said sleeve member to said second position to permit disengagement of said first and second tubular members.

22. Apparatus as set forth in claim 21 characterized in that said first and second tubular members are provided with connection means adapted for disengagement on rotation of said first tubular member through less than three hundred and sixty degrees.

23. Apparatus as set forth in claim 20 characterized in that said connection means includes a first portion provided on said first tubular member and a second portion provided on said second tubular member, said first portion being provided with a shield casing extending axially from said first portion around the exterior of said first tubular member, said first portion being turnable relative to said shield casing through an angle at least equal to that required for disengagement of said connection means.

24. Apparatus for use in removing pipe from a well comprising a first tubular member adapted for engagement with a second tubular member, said first tubular member being provided with first connection means cooperable with second connection means on the second tubular member and adapted for disengagement on turning of said first tubular member, said apparatus being provided with a shield casing means within which said first tubular member is movably disposed for turning sufficient to disengage said connection means; said apparatus being provided with means limiting relative axial movement of said shield casing and first tubular member; characterized in that said means for preventing axial movement comprises thrust bearing means mounting said shield member on said first connection means.

25. Apparatus according to claim 24 characterized in that said thrust bearing means includes annular groove means in an outwardly facing land on said first connection means and annular groove means in an inwardly facing surface of said shield casing disposed adjacent the first said annular groove means, and a plurality of balls in said groove means straddling the juncture thereof.

26. Apparatus according to claim 25 characterized in that said thrust bearing means allows unlimited rotation of said first connection means relative to shield casing in both directions and supports the full weight of said shield casing when the axis of the casing is vertical and the first connection means is at the lower end thereof.

27. Apparatus for use in removing pipe from a well comprising a first tubular member adapted for engagement with a second tubular member, said first tubular member being provided with first connection means cooperable with second connection means on the second tubular member and adapted for disengagement on turning of said first tubular member, said apparatus being provided with a shield casing means within which said first tubular member is movably disposed for turning sufficient to disengage said connection means; said shield casing being radially separated from said first tubular member throughout most of the length of the shield casing, characterized in that said apparatus includes bearing means at each end of said shield casing mounting said shield casing for turning movement of said first tubular member within said shield casing.

28. Apparatus according to claim 27 characterized in that the bearing means at the end of said shield casing most remote from said first connection means comprises a sleeve carried by said first tubular member telescopically received inside said shield casing.

29. Apparatus according to claim 27 characterized in that at least one of said bearing means is a thrust bearing limiting relative axial movement of said shield casing and first tubular portion.

30. Apparatus according to claim 29 characterized in that the bearing means closest to said first connection means is a ball thrust bearing and the other bearing means includes a sleeve carried by said first tubular member telescopically received in said shield casing.

31. Apparatus according to claim 30 characterized in that said sleeve is provided with a ring means extending out radially beyond the adjacent end of said shield casing to keep axial loads directed from said end toward said first connection means off of said shield casing, and said first connection means includes a shoulder extending out radially beyond the other end of said shield casing to keep axial loads directed from said other end toward the first said end off of said shield casing.

32. Apparatus according to claim 27 characterized in that said apparatus is provided with seal means to prevent the entrance of mud into space between said shield casing and first tubular member through the end of said shield casing adjacent said first connection means.

33. Apparatus according to claim 27 including drain means at said end of said shield casing to permit exit of material from said space.

34. A well construction as set forth in claim 14 characterized in that said connecting means further includes means to prevent relative rotation between said sleeve member and said lower tubular member while in said initial position, and guide means to prevent relative rotation between said sleeve member and said upper tubular member; said guide means comprising at least one vertical slot on the exterior of said sleeve member and a pin projecting inwardly from said upper tubular member to confine movement of said sleeve member from said initial to said final position to longitudinal motion relative to said upper member.

35. A well construction for removing pipe from an earth bore comprising an upper tubular member engageable with a lower tubular member and a sleeve member telescopically received within at least one of said tubular members on the interior thereof, said upper and lower tubular members being positioned within and in contact with the wall of such earth bore over the outer length of said lower member and at least the lower portion of the outer length of said upper member, one of said tubular members having flow passage means through its walls near the point of en gagement of said tubular members, said sleeve member being movable from a first position whereby said flow passages are blocked by a portion of said sleeve member to a second position whereby said flow passages are unblocked, said sleeve member being provided with means for an operating tool extended through one of said tubular members to make connection with the sleeve member, characterized in that said upper and lower tubular members are provided with connection means adapted for disengagement on rotation of said upper tubular member, and shield casing means rotatably disposed on and surrounding the lower portion of said upper tubular member.

36. A well construction for use in removing pipe from an earth bore comprising an upper tubular member adapted for engagement with a lower tubular member, said upper tubular member being provided with first connection means cooperable with second connection means on the lower tubular member and adapted for disengagement on turning of said upper tubular member, said upper and lower tubular members being positioned within and in contact with the wall of such earth bore over the outer length of said lower member and at least the lower portion of the outer length of said upper member, characterized by a shield casing means rotatably disposed on and surrounding the lower portion of said upper tubular member.

37. A well construction for removing pipe from an earth bore comprising an upper tubular member adapted for engagement with a lower tubular member, said upper tubular member being provided with first connection means cooperable with second connection means on the lower tubular member and adapted for disengagement on turning of said upper tubular member, said upper and lower tubular members being positioned within and in contact with the wall of such earth bore over the outer length of said lower member and at least the lower portion of the outer length of said upper member, characterized in that said well construction is provided with a shield casing means within which said upper tubular member is movably disposed for turning sufficient to disengage said connection means, and means on said upper tubular member limiting relative axial movement between said shield casing and upper tubular member.

38. Apparatus comprising upper and lower tubular members connected together by connection means disengageable by rotation of one of said tubular members relative to the other, valve means operable to provide flow communication between the interior and the exterior of said tubular members at a point adjacent said connection means, whereby washing fluid can be circulated from inside the tubular means to the exterior of the upper tubular member to remove surrounding material, so that the upper tubular member can be rotated to disengage said connection means, and shield casing means disposed on and surrounding said upper tubular member, extending upwardly from just above said point, said upper tubular member being rotatable with respect to said shield casing means sufficient to allow disengagement of said connection means when said shield casing means is prevented from rotating.

Claims

4. A method of removing well pipe means as set forth in claim 3 characterized in that said release of said special joint is effected by turning said well pipe means less than 360*.

6. Method according to claim 5 further characterized in that said shielding is effected by providing a casing around the pipe, and removing said casing simultaneously with said pipe and said part of said special joint.

12. A method of removing well pipe which is connected to other apparatus beneath the floor of a body of water, wherein the improvemEnt comprises the steps of: providing a special joint between said apparatus and said pipe which extends upwardly to a space above said body of water; pulling upwardly on a portion of said special joint to open passage means providing flow communication between the interior of said pipe and its surrounding environment; and circulating washing fluid through said passage means to remove mud and any other material surrounding said special joint, characterized by latching said portion of said special joint in an upward position to maintain said flow communication.

15. A well construction as set forth in claim 14 characterized in that said sleeve member is longitudinally movable upward from said initial position to said final position by an upward force on such connected tool and without rotation relative to said tubular members.

19. Apparatus for use in removing pipe from a well comprising a lower tubular member engageable with an upper tubular member and a sleeve member telescopically engageable with said tubular members on the interior thereof, said lower tubular member having flow passage means through its walls, said sleeve member movable from a first position whereby said flow passages are blocked by a portion of said sleeve member to a second position whereby said flow passages are unblocked, said apparatus being provided with guide means comprising at least one vertical slot on the exterior of said sleeve member and a pin projecting inwardly from said upper tubular member to confine movement of said sleeve member from said first to said second position to longitudinal motion relative to said upper member, said upper and lower tubular members being provided with connection means disengageable on rotation of said upper member relative to said lower member; characterized in that said second tubular member is provided with latch means disposed on said upper tubular member and engageable with said sleeve member in said second position to maintain said upper position and without hindering the disengagement of said upper member from said lower member.

21. Apparatus as set forth in claim 20 characterized in that said lock means is disengageable on movement of said sleeve member to said second position to permit disengagement of said first and second tubular members.

35. A well construction for removing pipe from an earth bore comprising an upper tubular member engageable with a lower tubular member and a sleeve member telescopically received within at least one of said tubular members on the interior thereof, said upper and lower tubular members being positioned within and in contact with the wall of such earth bore over the outer length of said lower member and at least the lower portion of the outer length of said upper member, one of said tubular members having flow passage means through its walls near the point of engagement of said tubular members, said sleeve member being movable from a first position whereby said flow passages are blocked by a portion of said sleeve member to a second position whereby said flow passages are unblocked, said sleeve member being provided with means for an operating tool extended through one of said tubular members to make connection with the sleeve member, characterized in that said upper and lower tubular members are provided with connection means adapted for disengagement on rotation of said upper tubular member, and shield casing means rotatably disposed on and surrounding the lower portion of said upper tubular member.